“Hippo Chase”. As we approached the camp the Selinda Reserve of northern Botswana our boat passed by a hippo resting in the water. I turned around to look back at the boat's wake and saw the hippo charging after us! The hippo must've been tired from an all-nighter because he was angry. He rose way up out of the water three times trying to chase our boat! He was coming at us with such force that he created a wake of his own. Photo location: Selinda Reserve of northern Botswana. (Photo and caption by Curtis Simmons/National Geographic Photo Contest)

“Double head vulture”. On the day of windy days during raptors migration some people in my country start to catch these tired raptors, so in this day we go to photograph some raptors and we saw these tow tired vultures, so we start to drag them away from the hunters until they reach a good hidden place, to make them safe until they start a new journey. Photo location: Kuwait. (Photo and caption by Mohd Khorshed/National Geographic Photo Contest)

Iraqi Kurdish refugees wait with children in Cukurca refugee camp in Turkey April 8, 1991. Reuters photographers have chronicled Kurdish refugee crises over the years. In 1991 Srdjan Zivulovic documented refugees in Cukurca who had escaped a military operation by Saddam Hussein's government in Iraq aimed at “Arabising” Kurdish areas in the north. Hundreds of thousands fled into Turkey and Iran. Images shot in recent months show familiar scenes as crowds of people flee Islamic State militants in Syria. There are as many as 30 million Kurds, spread through Turkey, Iraq, Syria and Iran. Most Kurds are Sunni Muslims, but tend to feel more loyalty to their Kurdishness, rather than their religion. (Photo by Srdjan Zivulovic/Reuters)

A resident jumps as he watches strong waves crash into shore as an effect of Typhoon Hagupit in Legazpi, Albay province, eastern Philippines on Sunday, December 7, 2014. Typhoon Hagupit knocked out power in entire coastal provinces, mowed down trees and sent more than 650,000 people into shelters before it weakened Sunday, sparing the central Philippines a repetition of unprecedented devastation by last year's storm. (Photo by Aaron Favila/AP Photo)

A tearful Beatle lover pleads unsuccessfully with a policeman to carry her fan button to Ringo, one of the four mop-top singers who drew squeals and shrieks from more than 30,000 spectators at two Indiana State Fair shows in Indianapolis on September 4, 1964. (Photo by Bob Daugherty/AP Photo)

A policewoman reacts as she falls off from a motorcycle while taking part in a rehearsal for Independence Day celebrations, in Ahmedabad, India August 4, 2017. (Photo by Amit Dave/Reuters)

Indian Air Force personnel parade during the 85th Air Force Day celebrations at Hindon Air Force base in Ghaziabad on October 8, 2017. (Photo by AFP Photo/Stringer)

Five-month-old baby elephant Fah Jam swims during a hydrotherapy treatment as part of a lengthy rehabilitation process to heal her injured front left foot at a rehabilitation center in Pattaya, Thailand January 5, 2017. The baby elephant was injured at three months old when she got stuck in an animal snare put up by villagers to prevent elephant intrusions in Chanthaburi province. (Photo by Athit Perawongmetha/Reuters)